Method and apparatus for processing video

ABSTRACT

Provided is an apparatus for processing a video. The apparatus for processing a video includes an image receiving module that is configured to receive encoded data, a filtering module that is configured to filter an image frame reconstructed from the encoded image, a block dividing module to divide the filtered image frame into a predetermined block dividing unit, a compression module to compress each of the plurality of blocks, to package the compressed plurality of blocks into a predetermined packaging unit, and to generate lookup table information corresponding to each of the packaged block, a frame buffer memory that is configured to record the packaged data, a first decompression module that is configured to perform first decompression of one or more of the recorded blocks corresponding to a particular frame for motion compensating by using the lookup table information, and a converter that is configured to decompress the recorded blocks to output sequentially by using the lookup table information.

TECHNICAL FIELD

The present invention relates to a method and apparatus for processing avideo, and more particularly, a method and apparatus for processing avideo, capable of improving bandwidth efficiency of a frame buffermemory.

BACKGROUND ART

The present invention results from a research, which has been carriedout as a part of work which was supported by the Technology InnovationProgram (10049498, 4K UHD HEVC/VP9 SoC for Streaming Smart Device)funded by the Ministry of Trade, Industry and Energy (MOTIE, KOREA).

Recent improvement of video processing algorithms allows a videoprocessing apparatus to process much larger-scale images.

Specifically, with need for ultrahigh definition (UHD), existing videocompression techniques have difficulty in accommodating sizes of storagemedia and bandwidths of transfer media. Accordingly, a novel standardfor compression of UHD video is needed. As a result, high efficiencyvideo coding (HEVC) has completely been standardized on January in 2013.The HEVC may be available for a video stream serviced through networks,such as the Internet, 3G, long term evaluation (LTE), etc, in which notonly UHD but also full high definition (FHD) or high definition (HD)videos can be compressed in accordance with HEVC.

A UHD TV is considered to mainly provide 4K (4096×2304 pixels) UHD at 30frames per second (fps) in the short term, while the number of pixels tobe processed per second is expected to continuously increase to 4K 60fps/120 fps, 8K 30 fps/60 fps, and the like. A bandwidth on demand perframe for a bidirectional frame prediction and filtering is expected toremarkably increase as well.

To deal with the increase in the processing bandwidths, a transmissionbandwidth between system modules or to the exterior should also beimproved based on performance or functions required for applications.

However, unlike the remarkable increase in the required processingbandwidth in response to an increase in image resolutions to beprocessed and frame rates, a bandwidth for transmission thereof islimited.

For example, a bandwidth for storing an image in a frame buffer memoryor extracting the image from the frame buffer memory may be limitedaccording to a minimum burst length of a memory application.

To overcome this problem, a method of compressing images which are inputand/or output in/out the frame buffer memory is taken into account, butfails to provide a remarkable bandwidth reduction effect.

Also, current frame buffer compression techniques are using a losscompression algorithm for obtaining high compression efficiency.However, the loss compression algorithm brings about a gradual decreaseof quality and a change of a compression data format.

Due to the format change, a process of searching for a frame buffermemory for random access is made complicated, thereby increasing athroughput and a processing time again.

DISCLOSURE Technical Problem

The present invention has been made keeping in mind the drawbacks of therelated art, and an object of the invention is to provide a videoprocessing apparatus and method, capable of improving bandwidthefficiency even without degradation of quality, by use of losslesscompression of a frame buffer.

Another aspect of the invention is to provide a video processingapparatus and method, which enables fast processing by providing acompression format of a frame buffer which is easy to access whilemaintaining a lossless state.

Also, another aspect of the invention is to provide a video processingapparatus and method, which enables maximizing effects of reducingbandwidth by diversifying compression methods for lossless compressionof a frame buffer.

Moreover, another aspect of the invention is to provide a videoprocessing apparatus and method, which enables improving a compressionefficiency by processing block dividing efficiently for frame buffercompression.

And another aspect of the invention is to provide a video processingapparatus and method, which maintains effects of reducing bandwidthduring decompressing and easy to access to memory for decompressing.

Technical Solution

In order to achieve the above object, there is provided an apparatus forprocessing a video according to one embodiment disclosed herein, theapparatus including an image receiving module to receive an encodedimage, a filtering module to filter an image frame reconstructed fromthe encoded image, a block dividing module to divide the filtered imageframe into a predetermined block dividing unit, a compression module tocompress each of the plurality of blocks, to package the compressedplurality of blocks into a predetermined packaging unit and to generatelookup table information corresponding to each of the packaged blocks, aframe buffer memory to record the packaged data; and a firstdecompression module to decompress at least one of the packaged blockscorresponding to a particular frame for motion compensating by using thelookup table information, and a second decompression module tosequentially decompress to output the decompressed blocks by the firstdecompression module by using the lookup table information.

The present disclosure provides a method for processing a video for avideo processing apparatus. The method for processing the video mayinclude receiving an encoded image, filtering an image framereconstructed from the encoded image, dividing the filtered image frameinto a predetermined block dividing unit, compressing each of theplurality of blocks, packaging the compressed plurality of blocks into apredetermined packaging unit, generating lookup table informationcorresponding to each of the packaged blocks, recording the packageddata and the lookup table information, firstly decompressing at leastone of the packaged blocks corresponding to a particular frame formotion compensating by using the lookup table information, and secondlyand sequentially decompressing to output the decompressed blocks byusing the lookup table information.

Meanwhile, the video processing method may be implemented as acomputer-readable recording medium having a program executable on acomputer.

Advantageous Effects

According to various embodiments, the present invention can provide anapparatus and method for processing a video, which is capable ofimproving processing efficiency by reducing bandwidths of a memorywithout degradation of quality, even for an image with a large number ofpixels (4K 60 fps/120 fps, 8K 30 fps/60 fps/ . . . , etc.) to beprocessed per second.

Also, according to various embodiments, the present invention canprovide an apparatus and method for processing a video, which is capableof improving processing performance by facilitating an access to acompressed frame buffer memory.

According to various embodiments, the present invention can provide anapparatus and method for processing a video, which is capable ofreducing overhead of input and/or output information in a frame buffermemory and facilitating a system configuration and improving stabilityof the system by reducing a variation of bandwidths.

Also, according to various embodiments, the present invention canprovide an apparatus and method for processing a video, which is capableof improving a performance of video processing, by selectively applyingcompression methods which may be different for each divided textureblock, and by selecting a compression method to maximize effects forreducing bandwidth.

Moreover, according to various embodiments, the present invention canprovide an apparatus and method for processing a video, which is capableof improving a performance of video processing by performing avariable-length coding for dual processed residual signal, and providingefficient methods for dividing and padding of texture blocks.

Also, according to various embodiments, the present invention canprovide an apparatus and method for processing a video, which is capableof improving a performance of video processing by easily accessing to aframe memory by using lookup table information, and by decompressing thebandwidth reduced compressed data by receiving them rapidly.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a configuration of a videodecoding apparatus in accordance with one exemplary embodiment disclosedherein.

FIG. 2 is a block diagram illustrating a configuration of a videodecoding apparatus in accordance with another exemplary embodimentdisclosed herein.

FIG. 3 is a block diagram illustrating in more detail a configuration ofa compression module of a video decoding apparatus in accordance with anexemplary embodiment disclosed herein.

FIG. 4 is a flowchart illustrating a video decoding method in accordancewith an exemplary embodiment disclosed herein.

FIG. 5 is a view illustrating a block dividing module of the videoprocessing apparatus in detail according to an exemplary embodimentdisclosed herein.

FIG. 6 is a flowchart for illustrating operation of the block dividingmodule in detail.

FIG. 7 is a flowchart for illustrating processes of compression for thedivided blocks according to an exemplary embodiment of the presentinvention.

FIG. 8 is a flowchart for illustrating processes of packaging blocksaccording to an exemplary embodiment of the present invention.

FIG. 9 is a view illustrating a decompression module of the videoprocessing apparatus in detail according to an exemplary embodimentdisclosed herein.

FIG. 10 is a view illustrating a converter of the video processingapparatus in detail according to an exemplary embodiment disclosedherein.

FIG. 11 is a view illustrating a line buffer module of the videoprocessing apparatus in detail according to an exemplary embodimentdisclosed herein.

FIG. 12 is a flowchart for illustrating operations of the converteraccording to an exemplary embodiment of the present invention.

FIG. 13 is a view illustrating a frame buffer memory compressedaccording to an exemplary embodiment disclosed herein.

FIG. 14 is a view illustrating a compression method and grouping inaccordance with an exemplary embodiment disclosed herein.

FIG. 15 is a view illustrating a lookup table in accordance with anexemplary embodiment disclosed herein.

FIG. 16 is a view comparing information stored in a frame buffer memoryaccording to an exemplary embodiment disclosed herein with the relatedart configuration.

FIGS. 17 to 24 are experimental data illustrating improved processingefficiency in case of applying an exemplary embodiment of the presentinvention.

MODE FOR INVENTION

Hereinafter, description will be given in detail of the preferredembodiments of the present invention to be easily practiced by thoseskilled in the art to which the present invention belongs, withreference to the accompanying drawings. However, the present inventioncan be embodied in many different forms and should not be construed aslimited to those exemplary embodiments set forth herein. Configurationsor elements unrelated to the description are omitted in the drawings asto clarify the present invention and like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being“connected with” another element, the element can be connected with theother element or intervening elements may also be present.

It will be understood that when an element is referred to as being “on”another element, the element can be directly on the other element orintervening elements may also be present between the two elements.

Unless specified otherwise, the terms “comprise,” “include,”“comprising,” and/or “including” specify the presence of elements and/orcomponents, but do not preclude the presence or addition of one or moreother elements and/or components. The terms “about” and “substantially”used in this specification to indicate degree are used to express anumerical value or an approximate numerical value when a mentionedmeaning has a manufacturing or material tolerance and are used toprevent those who are dishonest and immoral from wrongfully using thedisclosure of an accurate or absolute numerical value made to helpunderstanding of the present invention. The term “stage (of doing)” of“stage of” used in this specification to indicate degree does not mean“stage for.”

It will be noted that the expression “a combination thereof” in aMarkush statement means a mixture or combination of one or more selectedfrom the group consisting of elements mentioned in the Markushstatement, being construed as including one or more selected from thegroup consisting of the elements.

To encoding an actual picture (image) and a depth information mapthereof, High Efficiency Video Coding (HEVC) providing optimal codingefficiency among existing video coding standards, which is under jointstandardization by the Moving Picture Experts Group (MPEG) and VideoCoding Experts Group (VCEG), may be used as an example, without beinglimited thereto. A decoding apparatus according to an embodiment of thepresent invention may perform decoding through various types (MPEG2,AVC, etc.) of codecs using a frame buffer memory.

Generally, a video processing apparatus may include an encodingapparatus or a decoding apparatus. The encoding apparatus includes anencoding process and a decoding process, and the decoding apparatusincludes a decoding process. The decoding process of the decodingapparatus may be the same as the decoding process of the encodingapparatus. Thus, the following description will be made on the decodingapparatus

FIG. 1 is a block diagram illustrating a configuration of a videodecoding apparatus in accordance with one exemplary embodiment of thepresent invention.

As illustrated in FIG. 1, a video decoding apparatus 100 disclosedherein includes an entropy decoding module 110, a dequantizer/inversetransformer 120, an adder 180, a filtering module 130, a compressionmodule 140, a frame buffer memory 150, a decompression module 160, amotion compensation module 170, and an output module 190.

According to one exemplary embodiment of the present invention, thevideo decoding apparatus 100 may further include an intra/interchangeover switch and an intra prediction module. Here, this oneexemplary embodiment illustrates in more detail a method of compressingand packaging a reference frame for generating a prediction block and amotion compensating process upon inter-frame prediction (in an intermode) using the method.

The entropy decoding module 110 decodes a coded (encoded) bit streamtransmitted from a video encoding apparatus to separate into anintra-prediction mode index, motion information, a quantizationcoefficient sequence, and the like. The entropy decoding module 110 mayprovide the decoded motion information to the motion compensation module170.

The entropy decoding module 110 may provide the intra-prediction modeindex to the motion compensation module 170 and the dequantizer/inversetransformer 120. Also, the entropy decoding module 110 may provide adequantization coefficient sequence to the dequantizer/inversetransformer 120.

The dequantizer/inverse transformer 120 may transform the quantizationcoefficient sequence into a two-dimensional (2D) array of dequantizationcoefficients. The dequantizer/inverse transformer 120 may select one ofa plurality of scanning patterns for transformation. Thedequantizer/inverse transformer 120 may select one of the plurality ofscanning patterns on the basis of at least one of a prediction mode(that is, one of intra prediction and inter prediction) of a currentblock and an intra prediction mode.

The dequantizer/inverse transformer 120 may receive the intra predictionmode from the motion compensation module 170 or the entropy decodingmodule 110.

The dequantizer/inverse transformer 120 recovers (or reconstructs) thequantization coefficients using a quantization matrix, which is selectedfrom a plurality of quantization matrices, to the 2D array ofdequantization coefficients. Different quantization matrices may beapplied depending on a size of a current block to be reconstructed, anda quantization matrix may be selected for blocks of the same size basedon the prediction mode of the current block and the intra predictionmode.

The dequantizer/inverse transformer 120 inverse-transforms thereconstructed quantization coefficients to reconstruct a residual block.

The adder 180 adds the residual block reconstructed by thedequantizer/inverse transformer 120 and a prediction block generated bythe intra prediction module or the motion compensation module 170,thereby reconstructing a picture block.

The filtering module 130 filters off the reconstructed image, generatedby the adder 180. Artifacts due to picture loss generated during aquantization process may be reduced by the filtering. For example, thefiltering module 130 may perform a deblocking filtering process forremoving a blocking effect occurring in a reconstructed picture, anadaptive offset application process for compensating for a differencevalue from an original picture by each pixel, and an adaptive loopfiltering process for compensating for a difference value from anoriginal picture by each coding unit.

The frame buffer memory 150 is a memory to store a local decodingpicture which has been subjected to filtering by the filtering module130. The frame buffer memory 150 may store a plurality of frames orpictures for motion compensation. Data formats of stored and outputframes may be changeable by the compression module 140 and thedecompression module 160.

The frame buffer memory 150, for example, may include at least one ofstorage media, such as a flash memory type, a hard disk type, amultimedia card micro type, a card memory type (e.g., SD or XD memory),RAM and ROM (e.g., EEPROM, etc.).

The compression module 140 is a module to compress frames stored in theframe buffer memory 150 according to the video processing method of thepresent invention. The decompression module 160 is a module to extract arandom access target frame from the frame buffer memory 150, in responseto a request of the motion compensation module 170, and to perform adecompression (inverse compression) for the target frame.

Specifically, the compression module 140 according to an exemplaryembodiment of the present invention may perform lossless compression anduncompression to prevent degraded quality. Also, the compression module140 may generate compression and information and separately manage thecompression information in the form of a lookup table to realize abandwidth reduction.

For example, the compression module 140 may receive the loop-filteredframe, perform an adaptive entropy process using DPCM with respect tothe frame, and thus acquire losslessly-compressed texture segments.

The compression module 140 may generate compression information, whichincludes offset information related to each of the texture segments,package the texture segments by a burst length, and store the packagedtexture segments in the frame buffer memory 150 along with thecompression information. The frame buffer memory 150 may be an externalmemory which is connected through an AXI bus interface.

By virtue of the compression processing of the compression module 140and the operation of the decompression module 160 according to theexemplary embodiment disclosed herein, random access of the motioncompensation module 170 to the frame buffer memory 150 can befacilitated.

Also, 50% of the bandwidth reduction efficiency can result from thelossless compression and the storage based on the burst length accordingto the exemplary embodiment disclosed herein. The configuration of thecompression module 140 will be explained later.

The motion compensation module 170 reconstructs an intra prediction modeof a current block on the basis of the intra prediction mode indexreceived from the entropy decoding module 120, and generates aprediction block according to the reconstructed intra prediction mode.

Specifically, the motion compensation module 170 may randomly access thecompressed picture stored in the frame buffer memory 150 through thedecompression module 160 on the basis of motion vector information, andaccordingly generate a prediction block for a current block. When apoint-precision motion compensation is applied, a selected interpolationfilter is used to generate the prediction block. The generatedprediction block may be transferred to the adder 180.

Meanwhile, although not illustrated, the intra/inter changeover switchmay provide the prediction block, which has been generated by one of theintra prediction module and the motion compensation module 170, to theadder 180 based on an encoding mode.

In order to generate the prediction block for the motion compensation,the motion compensation module 170 may further include a demultiplexer,a motion information encoding mode determination unit, a merge modemotion information decoding unit, an advanced motion vector prediction(AMVP) mode motion information decoding unit, a prediction blockgeneration unit, a residual block decoding unit, and a reconstructedblock generation unit.

The motion information includes a reference picture index and a motionvector. The reference picture index indicates any one picture previouslyencoded and reconstructed.

When a current block is subjected to unidirectional inter predictiveencoding, the motion information indicates one of reference picturesincluded in list 0 (L0). On the other hand, when the current block issubjected to bidirectional predictive encoding, the motion informationmay include a reference picture index indicating one of the referencepictures of the list 0 (L0), and a reference picture index indicatingone of reference pictures of list 1 (L1).

Also, when the current block is subjected to the bidirectionalpredictive encoding, the motion information may include one or twopictures among reference pictures included in a combined list (LC) ofthe list 0 and the list 1.

The motion vector indicates a position of a prediction block within apicture indicated by each reference picture index. The motion vector maybe a pixel unit (integer unit) or a sub pixel unit.

For example, the motion vector may have a resolution of ½, ¼, ⅛ or 1/16pixel. When the motion vector is not an integer unit, the predictionblock is generated from integer pixels.

The demultiplexer demultplexes encoded motion information and encodedresidual signals from a bit stream received. The demultiplexer transmitsthe demultiplexed motion information to the motion information encodingmode determination unit, and the demultiplexed residual signals to theresidual block decoding unit.

The motion information encoding mode determination unit determines amotion information encoding mode of a current block. The motioninformation encoding mode determination unit may determine the motioninformation encoding mode of the current block according to skip_flag ofa bit stream received. The motion information encoding mode may include,but not limited to, at least one of a skip mode, a merge mode and anAMVP mode.

The skip mode may be applied when a skip candidate having the samemotion information as motion information on a current block is presentand a residual signal is 0. Also, the skip mode may be applied when thecurrent block has the same size as a coding unit. The current block maybe regarded as a prediction unit.

The merge mode may be applied when a merge candidate having the samemotion information as motion information on a current block is present.The merge mode may be applied when the current block has a differentsize from a coding unit or when a residual signal is present if thecurrent block has the same size as the coding unit. The merge candidatemay be the same as the skip candidate.

The AMVP mode may be applied when the skip mode and the merge mode arenot adopted. An AMVP candidate having the most similar motion vector toa motion vector of a current block is selected as an AMVP predictor.

The prediction block generation unit generates a prediction block of acurrent block using the reconstructed motion information. When themotion vector is an integer unit, the prediction block generation unitmay generate a prediction block of a current block by copying a block,which corresponds to a position represented by a motion vector in apicture indicated by a reference picture index.

However, when the motion vector is not an integer unit, the predictionblock generation unit may generate pixels of the prediction block frominteger pixels within the picture indicated by the reference pictureindex. In this instance, in a luma pixel, a predictive pixel may begenerated using a 8-tap interpolation filter. In a chroma pixel, apredictive pixel may be generated using a 4-tap interpolation filter.

The residual block decoding unit performs entropy decoding with respectto residual signals. The residual block decoding unit inversely scansentropy-decoded coefficients so as to generate a 2D block of quantizedcoefficients. Different types of inverse scanning may be used dependingon entropy decoding methods.

That is, different inverse scanning methods may be used for the interpredicted residual signals depending on CABAC-based decoding andCAVLC-based decoding. For example, diagonal raster inverse scanning maybe available for CABAC-based decoding, while zigzag inverse scanning maybe available for CAVLC-based decoding.

Also, different inverse scanning methods may be decided depending on asize of the prediction block.

The residual block decoding unit dequantizes a generated coefficientblock using a dequantization matrix. A quantization parameter isreconstructed to derive the quantization matrix. A quantization stepsize is reconstructed by each coding unit of a predetermined size orlarger. The predetermined size may be 8×8 or 16×16.

The residual block decoding unit may inversely transform the dequantizedcoefficient block to reconstruct a residual block. The reconstructedblock generation unit may add the prediction block generated by theprediction block generation unit and the residual block generated by theresidual block decoding unit.

In this manner, a current block may be reconstructed by using thereconstructed prediction block of the current block and the decodedresidual block of the current block. The reconstructed current block maythen be filtered and compressed to be stored in the frame buffer memory15. Such current block may be transferred to the motion compensationmodule 170 after being decompressed or output to the output module 190.

The output module 190 may process data output from the frame buffermemory 150, and display or externally transmit the processed data. Animage signal, a data signal, an OSD signal and the like, processed inthe output module 190 may be converted into R, G, and B signals,respectively, thereby being generated as driving signals.

Also, the output module 190 may further include a converter toreconstruct data compressed by the compression module 140 into an imagesignal. The output module 190 may include PDP, LCD, OLED, flexibledisplay, 3D display and the like to display the converted image signal.

FIG. 2 is a block diagram illustrating a configuration of a videodecoding apparatus in accordance with another exemplary embodimentdisclosed herein.

As illustrated in FIG. 2, a video decoding apparatus 100 according toanother embodiment according to the present invention includes anentropy decoding module 110, a dequantizer/inverse transformer 120, anadder 180, a filtering module 130, a compression module 140, a framebuffer memory 150, an decompression module 160, a motion compensationmodule 170, and an output module 190. The video decoding apparatus 100may further include an uncompression processing module 195.

In FIG. 2, the other components except for the compression module 140,the uncompression processing module 195 and the output module 190perform similar operations to those illustrated in FIG. 1, so detaileddescription thereof will be omitted.

As illustrated in FIG. 2, the uncompression processing module 195included in another embodiment disclosed herein may transfer an image,which has been filtered by the filtering module 130, directly to theoutput module 190 without passing through the compression module 140.

Specifically, the uncompression processing module 195 may transfer animage frame, which has been subjected to decoding and filtering, to theoutput module 190 in a line-by-line writing manner. To this end, theuncompression processing module 195 may include a separate buffermemory. A burst length of data may be predetermined as 64 bytes, 128bytes or the like.

In this manner, when a pure YUV image signal which is uncompressed istransferred to the output module 190, the output module 190 may outputthe image signal directly through a display or the like even withoutperforming the decompression (or inverse compression). Also, the outputmodule 190 may easily perform post-processing such as scaling by usingthe pure YUV image signal, which may result in extending a utilizationrange.

Therefore, the exemplary embodiment illustrated in FIG. 2 may notinclude a separate decompression processor, and the compression module140 may compress only a reference frame which is used for motioncompensation and store the compressed reference frame in the framebuffer memory, thereby improving video processing efficiency.

Hereinafter, description will be given in detail of the configuration ofthe compression module of the video encoding apparatus in accordancewith an embodiment disclosed herein.

In accordance with one exemplary embodiment of the present invention,the compression module 140 may include a picture buffer 141, a blockdividing module 142, a compression performing module 143, a packagingmodule 144, a compression data managing module 145, a compression flaggenerator 146, a group identifier generator 147, and a start offsetgenerator 148.

The picture buffer 141 may receive an image signal which has beenfiltered and output from the filtering module 130, and store the imagesignal in a buffer by each frame.

The block dividing module 142 acquires each frame from the picturebuffer 141, and divides the acquired frame into a plurality ofcompression blocks according to a size of a preset compression unit. Inthis embodiment of the present invention, the size of the compressionunit may be fixed, and each frame may be divided into 16×4 blocks, forexample.

The compression performing module 143 decides whether or not to compresseach block, and perform a lossless compression for blocks which havebeen decided to be compressed.

Specifically, according to the exemplary embodiment of the presentinvention, the compression performing module 143 may select one oflossless compression or uncompression for each divided block.

For example, the compression performing module 143 may select, as acompression method, a lossless variable-length compression method, suchas a DPCM entropy coding method.

However, the compression performing module 143 may compare a size ofdata subjected to the variable-length compression with a size ofuncompressed data, and select the uncompression method when the size ofthe data subjected to the variable-length compression is greater thanthe size of the uncompressed data.

In this manner, the compression performing module 143 may applydifferent compression methods for each block, and in some cases, employthe uncompression processing.

Also, the compression performing module 143 may select a method whichcan provide optimal bandwidth efficiency from the compression or theuncompression. Specifically, in order to overcome a degradation ofquality due to the loss compression and a reduction of bandwidthefficiency due to an increased calculation, which are caused in therelated art, the compression performing module 143 may also select amethod for maximizing only the reduced bandwidth efficiency,irrespective of a compression degree.

Accordingly, the compression performing module 143 may transferinformation indicating whether or not to compress a current block to thecompression flag generator 146.

Then, the compression flag generator 146 may generate a compression flagwhich indicates whether or not to compress the current block. Thecompression flag, for example, may have a form of 1-bit flag indicatingcompression or uncompression. The compression flag may correspond toeach block, and be transferred to the group identifier generator.

Meanwhile, the packaging module 144 groups data compressed by thecompression performing module 143 for each block, and packages thegrouped data.

The packaging module 144 may arrange the compressed blocks in one line,and group the arranged blocks on the basis of a burst length of theframe buffer memory 150. Each compressed block set grouped in thepackaging module 144 may be referred to as a burst group (BG).

For example, a burst length may be 128 bytes. In this instance, thepackaging module 144 groups the compressed blocks to be included in agroup based on the 128-byte burst length for packaging.

The packaging module 144 transfers the packaged texture data to thecompression data managing module 145 for each burst group. Thecompression data managing module 145 may perform writing for the framebuffer memory 150 for each burst group. This may bring about a reductionof a bandwidth variation resulting from the variable-length compression.Also, since compression efficiency of the lossless compression ismaintained, the packaging module 144 can maintain an improved state ofbandwidth efficiency (or a reduced state of bandwidths required) whilemaintaining system stability.

Also, the packaging module 143 may generate packaging information, whichindicates a group to which each block belongs in response to beingpackaged and a position within the group, and transfer the packaginginformation to the group identifier generator 147.

The group identifier generator 147 may generate a group identifier whichindicates a group, to which a currently-processed block belongs, fromthe packaging information. The group identifier may include a 8-bitburst group identifier (ID), for example.

The burst group identifier may indicate a relative position of eachgroup with respect to a specific base address.

The start offset generator 148 may generate start offset informationwhich indicates a start position of a current block within a group onthe basis of the packaging information. The offset information, forexample, may include 7-bit start byte offset information. The start byteoffset information may indicate a relative start position of each block.

Meanwhile, the compression flag generator 146, the group identifiergenerator 147 and the start offset generator 148 may transfer thecompression flag, the group identifier and the start offset information,which are related to the current block, to the compression data managingmodule 145, respectively.

The compression data managing module 145 may generate lookup tableinformation by combining the compression flag, the group identifier andthe start offset information, and record the generated lookup tableinformation in the frame buffer memory 150.

In more detail, the compression data managing module 145 may generatethe lookup table information corresponding to each block. Thecompression data managing module 145 may generate 2-byte lookup tableinformation by using 1-bit compression flag, 8-bit group identifier and7-bit offset information.

The generated lookup table information and the packaged data may berecorded in the frame buffer memory 150. As aforementioned, the packageddata may be recorded in the frame buffer memory 150 on the basis of theburst length.

When the 2-byte lookup table information is accumulated by each burstlength (for example, 128 bytes of lookup table information for 64 blocksare accumulated), the compression data managing module 145 may recordthe lookup table information in the frame buffer memory 150. Therefore,the recording of the lookup table information may be maintained based onthe burst length of the memory. This may result in maintaining theimproved bandwidth without change and improving system stability.

That is, in the embodiment of the present invention, in the packagingmodule 144, the unit of packaging the compressed texture block may bethe same as the unit of recording the lookup table information. Also,each unit may correspond to the burst length of the frame buffer memory150. This configuration may cause the improvement of the bandwidthefficiency.

The compression data managing module 145 may refer to lookup tableinformation relating to a previous block in order to generate lookuptable information relating to a current block. In this instance, forblocks belonging to the same group, the same data cannot be repetitivelyprocessed, thereby reducing an amount of data processed.

The frame buffer memory 150 records data output from thethusly-configured compression module 140. Specifically, the compressiondata managing module 145 may control and manage the data recorded in theframe buffer memory 150.

Accordingly, the frame buffer memory 150 may store and maintain thecompressed texture blocks, which have been packaged, by each frame, andalso separately store and maintain lookup table informationcorresponding to each frame.

Also, the lookup table information may include 2-byte information for16×4 block each. In one embodiment, the lookup table information mayinclude burst group identification information and start offsetinformation, which may allow for representing an offset, starting from abase address corresponding to each preset burst group, other than everyaddress of the frame buffer memory 150.

Here, information related to the base address corresponding to eachburst group may be separately stored and managed by the decompressionmodule 160 and the compression module 140, respectively. Therefore, thedecompression module 160 does not have to use all of the memoryaddresses to access the frame buffer memory 150.

Accordingly, the decompression module 160 can fast access a specificblock even when it receives only the lookup table information from theframe buffer memory 150.

Also, by virtue of presetting the burst group identifiers and thecorresponding base addresses and transmitting and receiving only thelookup table information associated therewith, overhead caused due tothe transmission and reception of all of the values of the memoryaddresses can be reduced. This may result in improvement of dataprocessing efficiency and reduction of bandwidths.

Meanwhile, the lookup table information included in the frame buffermemory 150 may be transferred to the decompression module 160. Thedecompression module 160 may access a specific position of the framebuffer memory 150 with reference to the lookup table information,thereby performing random access in response to a request of the motioncompensation module 170. To this end, the decompression module 160 mayinclude a first cache which requests the lookup table information fromthe buffer memory 150 and stores and manages the lookup tableinformation.

In more detail, when a specific frame is identified in response to therequest of the motion compensation module 160, the decompression module160 may acquire group identification information, start offsetinformation and a compression flag relating to each of blockscorresponding to the frame with reference to the lookup tableinformation.

The decompression module 160 may then access a specific address of theframe buffer memory 150 corresponding to each block on the basis of thegroup identification information and the start offset information.Accordingly, in the embodiment according to the present invention, aproblem that a long time is taken to search for a specific block, whichhas been caused in the related art compression method, can be overcome,and fast processing can be carried out while maintaining a bandwidthreduction effect.

The decompression module 160 may determine whether or not to decompresstext blocks according to the compression flags, and if required, performthe decompression. The decompression module 160 may reconstruct thedecompressed blocks to generate frame data requested by the motioncompensation module 170. The decompression module 160 may then transferthe generated frame data to the motion compensation module 170.

Afterwards, the motion compensation module 170 may generate theprediction block based on the motion vector information, asaforementioned, and transfer the generated prediction block to the adder180 to perform decoding of the image through the motion compensation ina sequential manner.

Hereinafter, description will be given of a video processing methodaccording to an exemplary embodiment of the present invention, withreference to FIGS. 4 to 12.

As illustrated in FIG. 4, the video processing apparatus 100 receives abit stream including encoded image data, and entropy-decodes thereceived bit stream (S100).

The video processing apparatus 100 performs dequantization and inversetransformation for the entropy-decoded image data (S110).

As aforementioned, the entropy decoding module 110 may decode theencoded bit stream which is transmitted from a video encoding apparatus,to separate into an intra prediction mode index, motion information, aquantization coefficient sequence and the like. The entropy decodingmodule 110 may provide the decoded motion information to the motioncompensation module 170. The entropy decoding module 110 may alsoprovide a dequantization coefficient sequence to the dequantizer/inversetransformer 120.

The dequantizer/inverse transformer 120 then transforms the quantizationcoefficient sequence into a 2D array of dequantization coefficients,selects one of a plurality of scanning patterns based on at least one ofa prediction mode (i.e., one of intra prediction and inter prediction)of a current block and an intra prediction mode, and reconstructs thequantization coefficients using a quantization matrix, which is selectedfrom a plurality of quantization matrices, to the 2D array ofdequantization coefficients. The dequantizer/inverse transformer 120inversely transforms the reconstructed quantization coefficients toreconstruct a residual block.

Afterwards, the video processing apparatus 100 reconstructs the imageusing the residual block and a prediction block, and filters thereconstructed image (S120).

As aforementioned, the adder 180 may reconstruct an image block byadding the residual block reconstructed by the dequantizer/inversetransformer 120 and the prediction block generated by the intraprediction module or the motion compensation module 170. The filteringmodule 130 may filter off the reconstructed image generated by the adder180. The detailed filtering method has been described.

Afterwards, the video processing apparatus 100 divides the filteredframe by each block (S130).

The compression module 140 may divide the image frame into blocks, inorder to compress and package image frame textures filtered by thefiltering module 130 and record the packaged image frame textures in theframe buffer memory 150.

The video processing apparatus 100 decides whether or not to compresseach divided block and a compression method (S140), and performs thecompression for each block according to the decided method (S150). Thevideo processing apparatus 100 then packages the compressed textureblocks (S160).

Afterwards, the video processing apparatus 100 stores lookup tableinformation and packaged data into frame buffer memory (S170).

FIG. 5 is a view illustrating a block dividing module 142 of the videoprocessing apparatus 100 in detail according to an exemplary embodimentdisclosed herein.

As shown in FIG. 5, the block dividing module 142 comprises a dividingstructure determining module 1421, a boundary padding module 1422 and ablock dividing processing module 1423.

The dividing structure determining module 1421 receives data of apicture from the picture buffer 141, and determines a dividing structureby analyzing the data of the picture received. In an embodiment ofpresent invention, the picture analyzed may be corresponding to oneimage which constructing one video frame. The picture may include dataof Y value, Cr value, and Cb value for each pixel which constructing thepicture.

The dividing structure determining module 1421 may analyze the pictureand identify horizontal and vertical lengths. The dividing structuredetermining module 1421 may determine a dividing structure based on thehorizontal and vertical length. Especially, the dividing structuredetermining module 1421 may use a predetermined block unit to determinethe dividing structure capable of dividing the horizontal and verticallengths of the picture by the block unit.

For example, the block unit may have a size of 16×4 pixels. The dividingstructure determining unit 1421 may determine the dividing structure todivide the picture into a plurality of blocks by segmenting thehorizontal length of the picture into 16 pixel unit and the verticallength of the picture into 4 pixel unit.

Moreover, the dividing structure determining module 1421 may determinewhether a size of the picture is multiple of a size of the block unit.It may not be that the size of the picture is multiple of a size of theblock unit because the size of the picture have many variationsaccording to its resolution.

Also, if the size of the picture is not multiple of a size of the blockunit, a size of boundary divided portion may be smaller than the size ofthe block unit. Thus, the dividing structure determining module 1421 maydetermine a boundary block having the size of the block unit whichincludes the boundary divided portion. The dividing structuredetermining module 1421 may transfer information of the boundary blockto the boundary padding module 1422.

Meanwhile, if the size of the picture is multiple of a size of the blockunit, the dividing structure determining module 1421 may determine thedividing structure and generate dividing structure information. Theblock dividing processing module 1423 may process dividing the pictureaccording to the dividing structure information to transfer each dividedtexture block into the compression performing module 143.

However, if the size of the picture is not multiple of a size of theblock unit, the dividing structure determining module 1421 may transfera boundary block information of the boundary block, which includes theboundary divided portion having different size with the size of theblock unit, to the boundary padding module 1422.

For example, if a horizontal size of the picture is 1610 pixels and thepicture is divided by 16×4 block unit based on the upper left end pixel,a horizontal boundary divided portion (horizontal 10 pixels X verticallength of the picture) is not fit into the size of the block unit. Thenthe dividing structure determining module 1421 may determine theboundary block including the boundary divided portion, and transferinformation of the boundary block to the boundary padding module 1422.

After receiving the information of the boundary block, the boundarypadding module 1422 performs padding for each of the boundary block bythe block unit.

Here, the boundary padding module 1422 may perform padding based on theinformation received from the dividing structure determining module1421. The boundary block may include the boundary portion as said and anon-picture region. And the boundary padding module 1422 may performpadding by inserting predetermined certain pixels into the non-pictureregion.

In particular, the boundary padding module 1422 can configure values ofthe pixels which padded in one direction to have same valuescorresponding to a horizontal (or vertical) boundary pixel of theboundary block. To this end, in the non-picture region of the boundaryblock, pixels having same value of the horizontal (or vertical) boundarypixel can be padded in horizontal (or vertical) direction.

According to the operation of the boundary padding module 1422, theboundary block can have texture data having size of the block unit, andthe video processing apparatus 100 can process continuously compressionand decompression of the block units having identical size. It makesreducing of variation of the texture size, and the bandwidth efficiencycan be improved.

Also, an embodiment of the present invention, by configuring values ofthe padded pixels into values of horizontal or vertical boundary valuesof the picture, compression efficiency using DPCM coding can be improvedby making zero residual signals in the horizontal or vertical direction.

When the padding is completed, the boundary padding module 1422 maytransfer the padded block unit into the block dividing processing module1423 or the dividing structure determining module 1421.

Meanwhile, the block dividing processing module 1423 may divide theboundary padded picture from the boundary padding module 1422 or thedividing structure determining module 1421 or original picture into aplurality of the block units. And all of the block units may haveidentical size. The plurality of the block units divided may betransferred sequentially to compression performing module 143.

FIG. 6 is a flowchart for illustrating operation of the block dividingmodule in detail.

First, the block dividing module 142 determines a dividing structure andgenerates dividing structure information (S200).

Next, the block dividing module 142 determines whether the vertical andhorizontal size of the picture is multiple of the predetermined size ofthe block unit.

As mentioned above, the dividing structure determining module 1421 mayidentify the horizontal and vertical size of the picture based on thepicture from the picture buffer 141. And, it may determine whether theidentified vertical and horizontal size of the picture is multiple ofthe predetermined size of the block unit.

If the size of the picture is not multiple of the dividing size of theblock unit, the block dividing module 142 determines boundary blocks(S203).

If the size of the picture is not multiple of the dividing size of theblock unit, the dividing structure determining unit 1421 may determinethe remaining portion of the picture smaller than the dividing blockunit size as the boundary region when the picture is divided by thedividing block unit and determine the region of the dividing bock unitincluding the boundary region as the boundary block. Thus, the boundaryblock may include both of the boundary region of the picture and thenon-picture region.

And, the block dividing module 142 detects boundary pixels of thepicture in the boundary block (S205).

The boundary padding module 1422 may obtain boundary block informationfrom the dividing structure determining module 1421. The boundary blockinformation may include position information of the boundary blocks, andidentify information of boundary region and non-picture region.

Then the boundary padding module 1422 may detect pixels corresponding toa boundary of the picture in the boundary block based on the boundaryblock information. Here, the boundary pixels may include a plurality ofpixels according to a horizontal or vertical length.

After, the block dividing module 142 performs padding to the non-pictureregion of the block based on the boundary pixels (S207).

As mentioned, the boundary padding module 1422 may pad same value as theboundary pixel into the non-picture region of the boundary block.Through this, the residual signal in a horizontal or vertical directionmay become zero, and the compression efficiency for DPCM codding can beimproved.

Then, the block dividing module 142 divides the picture according to thedividing structure information to output the picture by the block unitto the compression performing module 143.

FIG. 7 is a flowchart for illustrating processes of compression for thedivided blocks according to an exemplary embodiment of the presentinvention.

Referring to the FIG. 7, the compression performing module 143 obtainsthe blocks first (S301).

Each of texture blocks divided by the block dividing module 142 may betransferred sequentially to the compression performing module 143. Thecompression performing module 143 may perform compression using eachmethod for the each blocks.

To this end, the compression performing module 143 obtains the firstresidual signal by horizontal scanning (S303).

For example, the compression performing module 143, for the horizontalscanning, may allocate a pixel value in (y, x) coordinates of thepicture into a buffer, update the buffer as calculated value bycalculating difference with next pixel (y, x−1) according to thehorizontal scanning order. This may be performed to the each pixels ofeach blocks, and the horizontal scanned first residual signal may begenerated.

After, the compression performing module 143 obtains the second residualsignal by vertical scanning (S305).

For example, the compression performing module 143, for the verticalscanning, may allocate a pixel value in (y, x) coordinates of thehorizontal scanned first residual signal a buffer, update the buffer ascalculated value by calculating difference with next pixel (y−1, x)according to the vertical scanning order. This may be performed to theeach pixels of each blocks, and the vertical scanned second residualsignal may be generated.

Then, the compression performing module 143 selects a code word to applyto the second residual signal (S307).

The compression performing module 143, for lossless compression, mayperform a variable-length coding using one of a plurality of code words.The plurality of the code words may include a plurality of exponentialgolomb codes corresponding to order numbers different from each other.The compression performing module 143 may determine one of the codewords applying to the current block which is most efficient forbandwidth. For example, the compression performing module 143 maydetermine 3rd exponential golomb code as coding code word based on thebandwidth efficiency.

Next, the compression performing module 143 performs coding based on thedetermined code word (S309). Then, the compression performing module 143determines whether the bandwidth efficiency is increased by comparingwith the non-compression case (S311).

In the variable-length coding, although the codding has performed, thebandwidth which is needed for reading and writing the data to the memorycan be increased. Therefore, in the present invention, improvements ofthe bandwidth efficiency can be determined by comparing withnon-compression case of the current block.

If the bandwidth efficiency is increased, the compression performingmodule 143 outputs the compressed block (S313). And, if the bandwidthefficiency is not increased, the compression performing module 143outputs the uncompressed block (S315).

FIG. 8 is a flowchart for illustrating processes of packaging blocksaccording to an exemplary embodiment of the present invention.

The packaging module 144 may obtain the compressed or uncompressedblocks and package the blocks into a burst length of the memory. Also,the packaging module 144 may generate and transfer the lookup tableinformation to other modules according to the packaging.

First, the packaging module 144 obtains the first block compressed oruncompressed (S400).

Then, the packaging module 144 determines whether sum of block dataamounts accumulated in current block buffer and data amounts of thefirst block is bigger than the burst length of the memory, groups thedata accumulated in current block buffer (S403).

And, the packaging module 144 allocates a group identifier to thegrouped data, and generates offset information for each block in thegroup. The group identifier may correspond to a base address of thememory, and the offset information may indicate relative addresses ofblocks in the group. The group identifier and the offset information maybe included in the lookup table information, and managed separately withthe packaged data.

And, the packaging module 144 packages the grouped block data into theburst length (S407), output to the memory, and reset current blockbuffer (S409).

In particular, for improving bandwidth efficiency, if the grouped blockdata is smaller than the burst length, the packaging module 144 maypackage the data into the burst length by adding a dummy region to thegrouped block data.

Meanwhile, if the block buffer is reset or sum of block data amountsaccumulated in current block buffer and data amounts of the first blockis smaller than the burst length of the memory, the first block isaccumulated to the block buffer (S411).

FIG. 9 is a view illustrating a decompression module of the videoprocessing apparatus in detail according to an exemplary embodimentdisclosed herein.

Referring to the FIG. 9, the decompression module 160 may include apicture identification module 1601, a lookup table management module1602, a compression data management module 1603, a decompressionperforming module 1604, a picture reconstruction module 1605 and a datainterface module 1606.

The decompression module 160 may process obtaining a target picture forrandom access from the frame buffer memory 150 according to a request ofthe motion compensation module 170, and transferring the picture to themotion compensation module 170. Thus, the decompression module 160 canbe called as texture data processor for motion compensation includingdecompress module or decompressor.

The picture identification module 1601 may receive data requests formotion compensation from the motion compensation module 170, generatepicture identification information, and transfer the information to thelookup table management module 1602 or the data interface module 1606.

For example, the picture for motion compensation may be a random accesstarget picture for processing a motion compensation to the next frame,and the motion compensation module 170 may transfer data requestincluding identification information of the random access target pictureto the data interface module 1606. Also, for example, the target picturemay be a reference picture which is available to be used forinter-prediction of the current processing block. In this, the referencepicture used for inter-prediction of the current processing block inreference pictures included in a reference picture list may be indicatedby a reference picture index. Thus, the reference picture index may beconsidered as an indicator of the reference picture used forinter-prediction of the current processing block in reference picturesincluded in a reference picture list.

The reference picture may include STRP (Short term reference picture)and LTRP (Long Term Reference Picture). Here, STRP and LTRP may bereconstructed pictures stored in DPB (Decoded Picture Buffer). STRP maybe marked as “used for short-term reference” or “used for reference”.Also, LTRP may be marked as “used for long-term reference” or “used forreference”. For example, a POC (Picture Order Count) difference betweena decoding target picture and LTRP may have one of the value ranged ‘1’to ‘224-1’. The POC may indicate sequence of displaying of the picture.

The picture identification module 1601 may identify target picture usingthe reference picture index, etc.

The lookup table management module 1602 receives lookup tableinformation from frame buffer memory 150 through the data interfacemodule 1606. To this end, the lookup table management module 1602 mayinclude a cache memory for lookup table. Also, the cache memory mayinclude the lookup table information corresponding to each pictureidentification information.

And, the lookup table management module 1602 may search particularlookup table information corresponding to picture identificationinformation according to a request from the picture identificationmodule 1601, and transfer the searched lookup table information to thedata interface module 1606. The particular lookup table information mayinclude each position information on the frame buffer memory 150 for aplurality of block units in one picture. To this end, as mentionedabove, the lookup table information may include group identificationinformation and offset information.

The data interface module 1606 may receive compressed texture data fromthe frame buffer memory 150 by using particular lookup table informationcorresponding to the requested picture, and transfer the data to thecompression data management module 1603.

The data interface module 1606 can improve processing speed by directlyaccessing to particular position on the frame buffer memory 150according to the group identification information and the offsetinformation.

The compression data management module 1603 stores the compressedtexture data into a buffer and manages it. And the compression datamanagement module 1603 transfer compressed texture data corresponding toa requested picture to the decompression performing module 1604.

The decompression performing module 1604 determines whether compressionof each block in the compressed texture data, and performs decompressionfor compressed blocks. The decompression performing module 1604 canbypass uncompressed blocks to the picture reconstruction module 1605.

As mentioned, the lookup table information may include the compressionflag. Thus, the decompression performing module 1604 may determinewhether compressed or uncompressed by using the compression flag in thelookup table information.

Then, the decompression performing module 1604 may perform decompressionfor each compressed block. The decompression performing module 1604 mayfirstly identify the compression method applied to the compressed block,and perform decompression using the identified compression method. Thecompression method may be one of variable-length coding compressionmethods using a plurality of code words sets.

For identifying compression method for the compressed block of thedecompression performing module 1604, there may be many ways forsignaling. For example, the lookup table information may containidentification of code word used for the compression. Also, thedecompression performing module 1604 may identify the code word used forthe compression by data property of the compressed block. Moreover,identification information of the code word used for the compression maybe included in part of the compressed block data.

And, the picture reconstruction module 1605 collects decompressed oruncompressed blocks, and reconstructs a picture using them. The picturereconstruction module 1605 may identify size of the original picture,and remove added texture by padding to obtain a reconstructed picturesame as the original picture.

Reconstructed data of the picture reconstruction module 1605 may betransferred to the motion compensation module 170, and be used as thereference picture.

FIG. 10 is a view illustrating a converter of the video processingapparatus in detail according to an exemplary embodiment disclosedherein.

According to an embodiment of the present invention, the videoprocessing apparatus may comprise a converter 200, as shown in FIG. 1.The converter 200 may perform decompressing the texture in the framebuffer memory 150 by using a different method with the decompressionmodule 160, and output the texture in a linear way. In case of FIG. 2,the uncompression processing module 195 can be exist for transferringthe texture, but in case of configuration as in the FIG. 1, theconverter 200 can perform the decompression and output to the outputmodule 190.

In an embodiment of the present invention, the output module 190connected to the converter 200 may comprise a display interface, andwhen the output module 190 comprises a function of displaying, theoutput module 190 may be called as display module 190. The displaymodule 190 may comprise at least one of a liquid crystal display (LCD),a thin film transistor-liquid crystal display (TFT LCD), an organiclight-emitting diode (OLED), a flexible display, and a 3D display.

In particular, an output sequence of the converter 200 may have a rastersequence according to an interface format of the display module 190.Video signals having the raster order outputted from the converter 200may be directly displayed by the output module 190 or other displaysconnected. Accordingly, although the present invention brings an effectfor maintaining reduction of the bandwidth in case of the motioncompensation by using the lossless compression of the frame buffermemory 150, it minimizes influences of video display speed of byoutputting them through the converter 200 by using the frame buffermemory 150.

As shown in the FIG. 10, the converter may comprise a table informationobtaining module 201, a compression data obtaining module 203, seconddecompression performing module 205, a line buffer module 207 and aninterface converter 209, wherein the output module 190 can be called asdisplay module 190 including display functions.

The table information obtaining module 201 obtains the lookup tableinformation form the frame buffer memory 150.

The lookup table information, as mentioned above, may comprisecompression information, group identification information and offsetidentification information generated in process of compressing andpackaging by the compression module 140. The table information obtainingmodule 201, is different to in case of the compression module 160, mayobtain lookup table information for each block sequentially started fromthe first group and the first offset, and transfer it to the compressiondata obtaining module 203.

Then, the compression data obtaining module 203 obtains each compressedblock from the frame buffer memory 150 by using the obtained lookuptable information.

The compression data obtaining module 203 may access to the frame buffermemory 150 by using the lookup table information of the compressedblocks sequentially indicated by the table information obtaining module203, and may obtain compressed data of the texture blocks.

The second decompression performing module 205 performs decompression ofthe sequentially obtained blocks from the compression data obtainingmodule 203.

The second decompression performing module 205 may identify whethercompression of the obtained block by using the lookup table information,and may perform decompression of the compressed blocks. Methods ofdecompression can be identical with decompression module 160, andvariable-length decompression using one of code words can be used.

The line buffer module 207 temporarily stores the decompressed data, andoutput that line by line.

For example, the line buffer module 207 may store temporarilydecompressed data in 16×4 units. The line buffer module 207 may includeeach of 4 line buffers for luma and chroma, and the temporarily storeddata may be outputted in raster direction to the interface converter209.

FIG. 11 is a view illustrating a line buffer module of the videoprocessing apparatus in detail according to an exemplary embodimentdisclosed herein.

As shown in FIG. 11, the line buffer module 207 may perform sequentiallytemporal buffer writing and perform buffer reading in the rasterdirection.

For example, if the line buffer module 207 is capable of displayinterfacing in 4 k size format, the line buffer module 207 may include 4k×4 (=16 k) for luma and 2 k×4 (=8 k) for chroma, that is, 24 k bytessize of line buffer in total.

According to the present invention as shown in the FIG. 11, the linebuffer module 207 may simultaneously read data in raster scan orderduring temporarily writing the blocks. It makes minimize the size of theline buffer by outputting naturally without a double buffer.

Here, FIG. 10 can be described again.

The interface converter 209 converts the data outputted from the linebuffer module 207 in the raster scan order into an interface formatwhich is proper to the display module 190. For example, if thedecompressed data having 4:2:0 format, output format of the interfaceconverter 209 may be 4:42:2 or 4:4:4.

Then, the display module 190 performs display based on the video signalsfrom the interface converter 209.

FIG. 12 is a flowchart for illustrating operations of the converteraccording to an exemplary embodiment of the present invention.

First, the converter 200 obtains table information from the frame buffermemory 150 (S501).

As described, the table information obtaining module 201 may obtain thelookup table information from the frame buffer memory 150. The lookuptable information, as mentioned above, may comprise compressioninformation, group identification information and offset identificationinformation generated in process of compressing and packaging by thecompression module 140.

And, the converter 200 obtains compression data based on the tableinformation (S503).

As said above, the compression data obtaining module 203 may obtain eachof the compressed blocks from the frame buffer memory 150 based on theobtained table information. The compression data obtaining module 203may access to the frame buffer memory 150 by using the lookup tableinformation of the compressed blocks sequentially indicated by the tableinformation obtaining module 203, and may obtain compressed data of thetexture blocks.

After that, the converter 200 performs decompression of the compresseddata (S505).

The second decompression performing module 205 may perform decompressionfor the obtained blocks which are sequentially obtained by thecompression data obtaining module 203. The second decompressionperforming module 205 may identify whether compression of the obtainedblocks based on the lookup table information, and may performdecompression of compressed blocks. Descriptions of the decompressionprocess are same as described above, and can be omitted.

Then, the converter 200 outputs stored block data in raster directionsequentially.

The line buffer module 207 may output block data sequentially stored inline buffers in raster direction. In this, the line buffer module 207may temporarily store decompressed block data in the line buffers andmay perform line output in raster direction in simultaneously. Thereforehigh output speeds can be maintained with small size of the line buffer.

And, the converter 200 performs interface converting (S511), outputconverted video signals to display module 190.

The interface converter 209 may convert texture images outputted fromthe line buffer module 207 into a video display format according tointerface properties of the display module 190.

Then, the display module 190 can control display based on the convertedvideo signals.

FIGS. 13 to 14 are views illustrating a configuration of the divided andpackaged blocks according to an exemplary embodiment of the presentinvention.

(A) of FIG. 13 illustrates a whole frame divided into blocks. Asillustrated in (A) of FIG. 13, each frame may be divided into blockseach having a preset size. The preset size may be variable. 16×4 blockis assumed in the embodiment disclosed herein. If a size of a picture isnot a multiple of the preset size, an extra value of a blockcorresponding to an edge may be set to the same value as an edge pixel.

Meanwhile, as illustrated in FIG. 14, each of the divided blocks may beselectively compressed. Here, a compression method, as aforementioned,may be selected from one of uncompression, and variable-length codingcompression using DPCM, on the basis of reduction or non-reduction ofbandwidths.

Each compressed block may be packaged into each group according to aburst length. The packaging module 144 in this embodiment disclosedherein, as illustrated in a bottom of FIG. 14, may package the blocks bydesignating burst groups, respectively. A size of each burst group maycorrespond to a burst length of the frame buffer memory 150, and a groupidentifier may be assigned to each group.

Also, the packaging unit 144, as illustrated in FIG. 15, generateslookup table information corresponding to each block. The lookup tableinformation may include information for identifying each divided blockand a compressed or uncompressed state thereof from the packaged data.For example, the lookup table information may include 2-byte datacontaining 8-bit group identifier information, 7-bit start offsetinformation and 1-bit compression flag. The lookup table information maybe stored separately in the frame buffer memory 150.

Referring back to FIG. 13, (B) of FIG. 13 illustrates a storage space ofthe frame buffer memory 150 in which the packaged data is recorded in asequential manner. As compared with the whole frame of (A) of FIG. 13,the whole frame of (B) of FIG. 13 can store the compressed texture databy each block.

Here, numbers 0, 1, 2 and 3 at the left of the drawing may indicate baseaddresses corresponding to burst groups, respectively. Each block may beidentified according to burst group identification information and anoffset value. A region in which no texture data is present in each burstgroup may be filled with dummy data.

Meanwhile, (C) of FIG. 13 illustrates lookup table information which isstored separately in the frame buffer memory 150. The lookup tableinformation may be filled with 2-byte values corresponding to respectiveblocks, and arranged in the order of blocks constructing the wholeframe.

Therefore, the decompression module 160 may receive only the lookuptable information, as illustrated in (C) of FIG. 13, to identify textureblocks from the frame buffer memory 150, and can reconstruct an originalframe by performing decompression and reconstruction for the blocks.

Also, as aforementioned, the transmission and reception of only thelookup table information may result in a reduction of overhead causeddue to transmission and reception of every memory address. Consequently,improvement of data processing efficiency and reduction of bandwidthscan be acquired.

FIG. 16 is a view illustrating a size variation of the frame buffermemory 150 according to an exemplary embodiment of the presentinvention, which illustrates a configuration of the frame buffer memory150 for reducing bandwidths.

A left block diagram illustrates a typical frame buffer, and a rightblock diagram illustrates the frame buffer memory 150 which iscompressed and packaged according to the exemplary embodiment of thepresent invention. As illustrated in FIG. 16, unlike the related artframe buffer which stores decoded Y, Cb and Cr values, the frame buffermemory 150 according to the exemplary embodiment of the presentinvention may include compressed Y texture data, compressed C texturedata, lookup table information relating to the compressed Y, and lookuptable information relating to the compressed C.

The frame buffer memory 150 according to the exemplary embodiment of thepresent invention may include a buffer for storing the lookup tableinformation. A size of the buffer may be decided depending on an imageframe size. For example, when 2-byte lookup table information isgenerated for a block of 16×4 pixels, a buffer size for lookup tableinformation may be decided as 1/32*(frame size) for one frame.Therefore, the frame buffer memory 150 according to the embodiment ofthe present invention may further include an additional buffer region ascompared with the conventional frame buffer.

Also, when the 2-byte lookup table information is generated for theblock of 16×4 pixels, a region-based buffer size of the frame buffermemory 150 may be derived by the following formulas.

Compressed data for Luma:(PicX+15)/16*16*PicY

Compressed data for Chroma:(PicX/2+15)/16*16*PicY

Lookup table for Luma:(PicY+15)/16*(PicX+255)/256*128

Lookup table for Chroma:(PicY+15)/16*(PicX/2+255)/256*128

Description will be back to FIG. 4.

Afterwards, the video processing apparatus 100 transfers the lookuptable information and the packaged data to the decompression module 160according to the reference frame request of the motion compensationmodule 170 (S180).

The decompression module 160 of the video processing apparatus 100randomly accesses blocks constructing the corresponding frame using thelookup table information, and performs decompression of the blocks andframe reconstruction, thereby obtaining the reference frame (S190).

The video processing apparatus 100 transfers the obtained referenceframe to the motion compensation module 170 (S195).

FIGS. 17 to 24 illustrate test data indicating results obtained byapplying the video processing method in accordance with the exemplaryembodiment of the present invention.

To test the bandwidth reduction effect of the video processing methodaccording to the embodiment disclosed herein, various HEVC testsequences were used and classified into A to F according to image sizes.Bandwidths were estimated as a total amount of frame data in whichreading/writing of a memory was performed through a 128-bit businterface during a decoding process (while reading/writing of thereference frame was performed for motion compensation). Also, fourdifferent qp values (22, 27, 32 and 37) for each sequence were used.

Considering the whole results of FIGS. 17 to 24, it was understood thatthe video processing method according to the exemplary embodimentdisclosed herein could save 56% of bandwidths on average rather thanpure bandwidths when a loop filter module performs writing. Also, it wasunderstood that the video processing method according to the exemplaryembodiment of the present invention could save 59% of bandwidths onaverage rather than pure bandwidths when a motion compensation moduleperforms writing.

FIGS. 17 and 18 illustrate compensation results in a classifying mannerof average bandwidths due to a frame buffer compression of the videoprocessing method according to the embodiment disclosed herein and purebandwidths without compression performed.

FIG. 17 illustrates a bandwidth reduction rate when the decodingapparatus illustrated in FIG. 1 processes a video in accordance with oneexemplary embodiment of the present invention, and FIG. 18 illustrates abandwidth reduction rate when the decoding apparatus illustrated in FIG.2 processes a video in accordance with another exemplary embodiment ofthe present invention.

Meanwhile, FIGS. 19 to 21 are graphs visually illustrating comparisonresults according to each condition as FIGS. 17 to 18. As can beunderstood through the graphs, a remarkable bandwidth reduction can beobtained according to the embodiment of the present invention.

FIG. 23 also illustrates maintenance of bandwidth stability as well asthe bandwidth reduction according to the video processing methodaccording to the exemplary embodiment of the present invention. Withregard to results of the frame buffer compression (line marked with FBC)according to the embodiment of the present invention in FIG. 19, it canbe understood that an almost uniform value is maintained in spite of thedrastic change of uncompressed image information while about 70% ofbandwidths is reduced rather than uncompression (Uncomp). Therefore, thepresent invention can maintain bandwidth stability and derive anadvantageous result for cache design.

FIG. 24 illustrates that an average bandwidth upon the frame buffercompression (line marked with FBC) is reduced below 20% rather than abandwidth of uncompressed (Uncomp) data. The embodiment according to thepresent invention can allow for processing high-resolution image whilemaintaining image quality by virtue of the bandwidth reduction.

The aforementioned methods according to the present invention can bewritten as computer programs to be implemented in a computer and berecorded in a computer readable recording medium. Examples of thecomputer readable recording medium include read-only memory (ROM),random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks,optical data storage devices, and carrier waves, such as datatransmission through the Internet.

The computer readable recording medium can also be distributed overnetwork coupled computer systems so that the computer readable code isstored and executed in a distributed fashion. Also, functional programs,codes, and code segments for accomplishing the present invention can beeasily construed by programmers skilled in the art to which the presentinvention pertains.

While exemplary embodiments of the present invention have been shown anddescribed, the present invention is not limited to the describedexemplary embodiments. Instead, it would be appreciated by those skilledin the art that various changes and modifications may be made to theseexemplary embodiments without departing from the spirit and scope of theinvention as defined by the appended claims, and these changes andmodifications are not construed as being separated from the technicalidea and prospects of the present invention.

1. A video processing apparatus comprising: an image receiving modulethat is configured to receive encoded data; a filtering module that isconfigured to filter an image frame reconstructed from the encodedimage; a block dividing module to divide the filtered image frame into apredetermined block dividing unit; a compression module to compress eachof the plurality of blocks, to package the compressed plurality ofblocks into a predetermined packaging unit, and to generate lookup tableinformation corresponding to each of the packaged block; a frame buffermemory that is configured to record the packaged data; a firstdecompression module that is configured to perform first decompressionof one or more of the recorded blocks corresponding to a particularframe for motion compensating by using the lookup table information; anda converter that is configured to decompress the recorded blocks tooutput sequentially by using the lookup table information.
 2. Theapparatus of claim 1, the converter comprising: a table informationobtaining module configured to obtain the lookup table information fromthe frame buffer memory; and a compression data obtaining moduleconfigured to obtain sequentially the recorded blocks based one thelookup table information, wherein the lookup table informationcomprising compression information, group identification information andoffset information corresponding to each block.
 3. The apparatus ofclaim 1, the converter comprising: a second decompression performingmodule configured to decompress sequentially the recorded blocks; and aline buffer module configured to receive and store temporarily thesequentially decompressed blocks to output in a raster direction.
 4. Theapparatus of claim 3, wherein the line buffer module stores temporarilythe sequentially decompressed blocks in sequence, and outputstemporarily pre-stored decompressed blocks in the raster directionsimultaneously.
 5. The apparatus of claim 1, the converter comprising:an interface converter configured to convert outputted decompressed datainto an interface format for displaying.
 6. The apparatus of claim 5,further comprising: a display configured to control display based onoutput data of the interface converter.
 7. The apparatus of claim 1, thefirst decompression module comprising: a lookup table management moduleconfigured to manage the lookup table information by a cache memory. 8.The apparatus of claim 1, wherein the compression module performscompression or bypass for each of the plurality of the blocks using aplurality of code words different from each other according to theproperties of the blocks.
 9. The apparatus of claim 1, wherein thepredetermined unit into which the compressed plurality of blocks arepackaged is the same as a burst length of the frame buffer memory.
 10. Avideo processing method for a video processing apparatus, the methodcomprising: receiving an encoded image; filtering an image framereconstructed from the encoded image; dividing the filtered image frameinto a predetermined block dividing unit; compressing each of theplurality of blocks; packaging the compressed plurality of blocks into apredetermined packaging unit; generating lookup table informationcorresponding to each of the packaged block; recording the packaged dataand the lookup table information; and performing first decompression ofone or more of the recorded blocks corresponding to a particular framefor motion compensating by using the lookup table information; andperforming second decompression of the recorded blocks sequentially byusing the lookup table information.
 11. The method of claim 10, theperforming second decompression comprising: obtaining the lookup tableinformation form frame buffer memory; and obtaining the recorded blockssequentially based on the lookup table information, wherein the lookuptable information comprising compression information, groupidentification information and offset information corresponding to eachblock.
 12. The method of claim 10, second decompression comprising:decompressing the recorded blocks sequentially; storing temporarily thesequentially decompressed blocks; and outputting the temporarily storedblocks in raster scan order.
 13. The method of claim 12, the outputtingcomprising: storing temporarily the sequentially decompressed blocks insequence during outputting temporarily pre-stored blocks in raster scanorder simultaneously.
 14. The method of claim 10, second decompressioncomprising: converting outputted decompressed data into an interfaceformat for displaying.
 15. The method of claim 14, further comprising:controlling display based on based on the converted data from interfaceconverter.
 16. The method of claim 10, the first decompressingcomprising: managing the lookup table information by using a cachememory.
 17. The method of claim 10, the compressing comprising:performing compression or bypass for each of the plurality of the blocksusing a plurality of code words different from each other according tothe properties of the blocks.
 18. The method of claim 10, wherein thepredetermined unit into which the compressed plurality of blocks arepackaged is the same as a burst length of the frame buffer memory.
 19. Anonvolatile recording medium with a program recorded therein forexecuting the method according to claim 10 in a computer.